Newly compiled gravity and magnetic data within the north-central United States were used to investigate the crustal structure of the region's Precambrian geology. Gray-scale imaging, gravity stripping, enhanced magnetic gradients, and polynomial trend surfaces were used to delineate the potential field characteristics of each of the Precambrian orogens. This analysis expanded on the previous regional investigations by suggesting that several crustal blocks (or regions of different lithologies/crust thickness) may exist in each of the known orogens. In addition, the study found that the interpreted location of the orogen boundaries varied depending on the type of potential field analysis used. The...